Glossary of Technical Terms

Account
The resources on a server or computer that can be accessed and the activities that are
permitted when the Account Credentials are supplied by a user.

Account Credentials
The information that must be in place before a user gains access to a computer account.
At the most basic level, a user must supply a username and password.

Admin Account
An account on a device that allows unrestricted access.

Administrator
The person responsible for administering a device. Administrators are able to do things
that Users are prevented from doing, such as creating and deleting user accounts,
changing the admin account password, changing system settings, installing and deleting
software.

Analog Data
Audio and video recorded in the grooves of an LP record or on magnetic tape in a from that
generates a rapidly changing voltage waveform when put in a playing or transmitting device.
For example, the groove in an LP record vibrates a record player stylus and generates a
voltage waveform that corresponds to the frequency and volume of the recorded sound; the
signal is amplified and converted into sound by a speaker. Prior to the invention of digital
devices, all audio and video data was recorded in analog form. The term came into general
use when Audio CDs were first marketed in the 1980s—it was used to distinguish
recordings made with the older technologies and then digitized to create the CD master
from those that were both recorded and mastered on digital devices.

Android
An operating system used in mobile phones, tablet computers, digital media players and
PCs. It is based on the Linux operating system. It is supported by Google and Amazon.

App
A program installed on a mobile device or media player to give it a specific functionality.
For example, the Weather App on a mobile phone allows the user to check the Bureau of
Meteorology Forecast for a particular area. The YouTube app on a mobile phone allows the
user to access videos on the YouTube site. See Application.

App Store
A repository or server on the Internet from which apps for mobile devices may be obtained.
An App Store is usually accessed via an preinstalled App on the mobile device. Users may be
required to establish an account and to log in via a user name and password.
Apps can usually be searched for by name, or by description.
Once an app has been selected, download and installation is usually automatic.
Some apps can be downloaded and installed without charge, while others must be purchased.
The licence conditions may allow a purchased app to be installed on multiple
devices via the same app store account.
App stores are usually device or operating system specific.
for example: the Apple App Store,
the Microsoft App Store, the Samsung App Store,
the Google Play App store the Amazon App store.

Apple TV
A media player marketed by Apple that allows Apple devices such as PCs, iPhones and iPads
to stream data to a TV screen and allows content on selected Internet sites to be freely
accessed or purchased and streamed to the TV.

Application
A program installed on a PC to give it a specific functionality. For example
a word processor facilitates the creation of documents; a spread sheet allows facilitates
the manipulation of an array of calculations; a web browser provides a means of access data
stored in Internet sites; a media player allows music and video files to be listened to
or viewed.

ASCII
American Standard Code for Information Interchange. Digital data exchange began with Morse
Code and the Telegraph—an operator pressing a telegraph key sent text letter by letter,
encoded as dots and dashes. Ticker-tape and other automatic transmission/reception systems
used seven-bit ASCII code. Early PCs used 8-bit microprocessors and 8-bit memory chips and
were designed to process text characters stored as 8-bit bytes. Standard ASCII code was
extended in various ways to store punctuation symbols and special characters.

ASDL
Asymmetric Digital Subscriber Line. A means of connecting a premises to the Internet via
a system that simultaneously transmits voice and digital data on a phone line. The term
asymmetric indicates that the incoming data rate is faster than the outgoing data rate.
See DSL.

Audio File
A set of digital data that stores recorded sound in memory or is used to transmit recorded
sound between devices on a network.

Authentication
The process used by a computer or server to allow only authorized users to access data or
make changes to a system. For example:
1) on attempting to start up a PC a user may be required to supply a username and password.
2) on attempting to access data stored on a system, the user may be requested to supply
the username and password of an account permitted to access the data.
3) on attempting to install software or change system settings, the user may be prompted
to supply the username and password of an account with administrator access.
Some systems require a second level of authentication. An online bank user, for example,
must supply an account ID and password to log on. To make a payment, the user may be
expected to supply a code sent to the user's phone by SMS. That is an example of
two-factor authentication:
1) the user must be able to supply a username and password
2) and possess the phone to which the SMS code is sent.
Some authentication systems utilize other factors such as
fingerprint recognition, iris-scan recognition, voice recognition, insertion of a USB
dongle key, etc.

Bit
A binary digit; a zero or a one. The smallest element of a digital memory device, capable
of storing a zero or a one. All digital data is stored as a set of binary digits. See
Byte, Digital Memory, Digital Storage, Memory.

Bluetooth
A close-proximity wireless standard for connecting peripherals such as microphones and
speakers to digital devices. Audio on a mobile phone can be played to an audience if the
phone is connected to a Bluetooth speaker. A mobile phone connected via Bluetooth to a
vehicle's audio system can be operated without taking the phone out of one's pocket.
Bluetooth has a range of up to ten metres. Once a Bluetooth pairing has been established,
a device automatically connects and disconnects as it moves in and out of reception range.

Broadband
A high-speed digital data service. The Australian Bureau of Statistics classifies
broadband as anything more than 256 Kbps (0.25 Mbps)—about five times the transmission
speed obtainable from a dial-up modem. The NBN is planned to connect 90% of the premises
in Australia to a service that delivers 50 Mbps by 2020. In the USA and other parts of
the world, broadband services that deliver 1,000 Mbps (1 Gbps) are being rolled out in 2015.

Byte
An array of 8 bits in a digital memory. Sufficient memory to store a single alphanumeric
character of recorded text. The bit values of several characters in the extended ASCII
system are:0100 0001 - uppercase “A”
0110 0001 - lowercase “a”

Cast
To send media stored on a portable device to a display device such as a TV set. Casting
allows data stored on a personal device such as a mobile phone or portable PC to be shared
with an audience.

CAT5 Cable
Category 5 is a specification standard for data transmission cable capable of transmitting
data at up to 100 Megabits per second. CAT 5 cable has four pairs of twisted wires. Only
two pairs are used to transmit data—the others are not connected. The cables are terminated
by RJ45 connectors.

CAT5e Cable
Category 5 extended is a specification standard for data transmission cable capable of
transmitting data at up to 1000 Megabits per second. CAT5e cable has four pairs of
twisted wires. All four pairs are used to transmit data. The cables are terminated by
RJ45 connectors.

Client
A digital device programmed to interact with a server computer. For example
a web browser on a PC is a client that accesses data from a web server on the Internet;
ABC iView is a client app on some smart TVs, digital media players, mobile phones and
tablet PCs that accesses media on the ABC's server on the Internet.

Controller
A digital media device used to arrange the displaying or playing of content on a TV or
other media playing device. Purpose-built remote controls are supplied with TV sets,
Digital Video Recorders and Digital Media Players. Mobile phones and tablet PCs can be
programmed to act as controllers of those same devices.

CPU
The Central Processing Unit of a computer. The circuitry via which the computer
manipulates data—for example, moves data to and from memory, transmits data via a LAN
port, reads and writes data to a storage device, etc..

Data
Information stored as an array of binary bits in digital memory or transmitted as a
stream of binary bits via a wire or a wireless connection. Various data recording and
transmission standards have been developed to store documents, images, audio, video, etc..

Data Packet
A portion of a file in transit between devices, a fixed length set of data packaged for
transmission between devices on a network. As well as the data being sent, a data packet
contains metadata identifying the sender and recipient IP addresses, the filename, the
file type, the packet number, the number of packets that make up the file, and a checksum
that allows the receiver to check the integrity of the received packet.

Data Transfer
The process of reading data stored in memory, converting it into a signal stream that
can be sent across a network, and converted back into a data to be displayed by the
receiving device and/or stored in the receiving device's memory. See
Data Packet, Memory.

Data Transfer Rate
A measure of the speed at which data is transmitted of received. The various units used
to specify transmission speeds are:

Bits per second

bps

Bytes per second

Bps

Kilobits per second

Kbps

Kilobytes per second

KBps

Megabits per second

Mbps

Megabytes per second

MBps

Gigabits per second

Gbps

Note: b signifies the rate is specified in bits. B signifies the rate is expressed in
bytes. One byte is equal to 8 bits. See Bit, Byte, Digital Storage.
There are about one million letters in the text of a three hundred page paperback
novel—it could be stored in one megabyte or eight megabits of
digital memory. High transfer rates are mind-boggling—a device
that can transmit data at one gigabit per second could
transmit the text of 125 paperback novels in one second.
(125 x 8,000,000 = 1,000,000,000 bits = one gigabit)

Desktop
A conveniently accessible folder on a PC’s storage space that hold’s work in progress. See
File System.

DHCP
Dynamic Host Control Protocol. A system for automatically allocating unique IP Addresses
to devices when they connect to a LAN. On a home LAN, the WiFi Modem Router usually acts
as a DHCP server.

Dial-up Modem
A device that translates digital signals to audible tones that can be carried on standard
phone lines and vice versa. Ordinary phone calls cannot be made or received when a dial-up
modem is being used, for the system uses the entire signal carrying capacity of the line.

Digital Data
See Data

Digital Media
See Media

Digital Memory
Components in devices for temporarily storing work in progress and for long time
storage of data. See
RAM, ROM, Flash RAM, HDD storage, SSD storage. See Memory for a discussion of saving
and retrieving files from digital memory.

Digital Storage
The unit measure of digital storage is the byte, a array of 8 bits, a memory element
sufficient to store one alphanumeric character, an “A” or a “Z” for example. Larger
measures that increment by certain powers of 2 are used:

Byte

B

1 byte

2^0 bytes

Kilobyte

KB

1,024 bytes

2^10 bytes

Megabyte

MB

1,048,576 bytes

2^20 bytes

Gigabyte

GB

1,073,741,824 bytes

2^30 bytes

Terabyte

TB

1,099,511,627,776 bytes

2^40 bytes

The numbers are astounding—one megabyte can hold the text of a paperback novel or six
seconds of hi-fi quality audio. One terabyte could hold a million books (one would
need two or three thousand years to read them) or 1,600 hours of audio—(70 days)
of non-stop listening). A 1TB USB hard disk can be purchased for less than $100 (2015).

DLNA
Digital Living Network Alliance. A consortium of consumer electronics companies formed to
develop and promote interoperability guidelines for sharing digital media among devices.
The set of standards developed by the Alliance.

Document File
A set of digital data that stores in memory the text and images that make up a document
or is used to transmit the document between devices on a network.

DSL
Digital Subscriber Line. A means of connecting a premises to the Internet via a system
that simultaneously transmits voice and digital data on a phone line. Incoming data rate
is transmitted at the same rate as outgoing data rate. As a cost saving measure, homes
are usually connected via ADSL See ADSL.

Encryption
A means of transmitting data securely. The transmitting and receiving devices share a key.
All data is encoded prior to transmission and decoded after reception. Encoding and
decoding happen in real time in devices that have the shared key. An eavesdropper who
does not have the shared key would require an unrealistic amount of computing power and
time to decode the transmissions.

Ethernet
A set of wiring and transmission standards for transmitting digital data between network
devices.

Ethernet Cable
See CAT5 Cable, CAT5e Cable,

File
A set of digital data stored in memory or used to transmit data across a network. See
Document File, image File, Audio File, Video File.

File Format
A standard for storing particular sets of digital data—an image, a audio track, or a
movie, for example—in memory and transmitting them between networked devices. Various
file formats have been developed for various types of digitally recorded information.
See Audio File, Document File, Image File, Media File, Video File.

File Server
A networked storage device that is programmed to allow other devices on the network to
access files on the File Server, save files to it, create folders, move files between
folders, rename files and folders and delete files and folders, etc., etc.. When a device
logs on to a File Server, it mounts as a volume on the local machine and can be accessed
in the same way as the local hard disk drive or a locally attached USB drive.

File System
That part of a PC's operating system that allows users to access and manage the files and
folders stored on the system. On Microsoft Windows PCs, the File System’s Graphic User
Interface (GUI) is called Windows Explorer or simply Windows. On Mac PCs, the File System
GUI is called Finder. The Desktop folder often displays by default when a PC is started up.
The Desktop is conveniently accessible folder on the inbuilt HDD or SSD that hold’s work
in progress. The items placed there display as icons. Some users store all or most of the
files they create in their PC's desktop folder.
The File System also allows the user to access other files and folders stored on the PC's
inbuilt drive/s, locally attached USB hard disk drives and USB Flash memory drives and File
Servers on the LAN. If a VPN connection has been arranged, the file system even allows
files stored on remote severs and PCs to be accessed across the Internet.

Firmware
Operating system code stored in Flash Memory in WiFi Modem Routers, TVs, Digital Media
Players, etc. From time to time, manufactures release Firmware updates to fix bugs in the
code or add new features to their devices.

Flash Memory
Solid-state memory circuitry that continues to hold data when disconnected from a power
source. Flash memory chips are incorporated into USB thumb drives and memory cards and
used to hold Firmware in some digital devices.

Gateway
The LAN device that handles transfer of data packets between devices on the LAN and
devices on the wider Internet. On small business or home LANs, the WiFi Modem Router
serves as the Gateway.

Gigabyte
A block of memory that stores 1,073,741,824 bytes of data.

Google Chromecast
A HDMI Media Player dongle that adds Internet and LAN connectivity to a TV via WiFi.
The Chromecast plays media on Internet sites and LAN devices. The content to be played
is selected via Chromecast compliant apps on iOS and Android mobile devices or via the
Google Chrome browser on a PC.

Graphic User Interface
Early computers had text-centric operating systems—tasks were completed by typing
commands on a keyboard—the computer’s command language had to be learned or a user to
accomplish tasks. Graphic User Interfaces (GUIs) began appearing on home
computers in the mid 1980s. All PCs now have GUI operating systems. Some common GUI
features are:
- Menus that offer users choices.
- A point-and-click mouse or track pad that is used to make selections.
- Files and folders and the disks they are saved are displayed as icons.
- Navigation to required data is by pointing and clicking.
- A Desktop, a particular folder on the user’s computer that serves as
a place to store work in progress and stores icons that
connect the user to other storage spaces.

ISM Band
The industrial, scientific and medical radio bands that are reserved internationally for
the use of radio frequency energy for industrial, scientific and medical purposes other
than telecommunications. The 2.4 GHz and 5 GHz WiFi bands are in the ISM reserved
spectrum space.

Kilobyte
A block of memory that stores 1,024 bytes of data.

LAN
Local Area Network. A Set of networked PCs, mobile devices and media devices linked via
Ethernet cable and WiFi.

LAN Port
A socket and associated electronic circuitry and software on a PC or network device
designed to connect to other devices via Ethernet Cable.

Linux
An operating system derived from Unix and maintained and freely distributed by various
groups. Versions of Linux form the operating system of WiFi modem routers, digital media
players, mobile phones, tablet computers, PCs, NAS units and Internet servers.

Prior to the Digital Age, media was produced by and transmitted to consumers by Mass Media
organizations—Newspaper Corporations, Book Publishers, Radio Broadcasters, Film Studios,
Recording Companies and Television Networks. The digital age has democratized media
production and distribution—private individuals now have
the means of producing and distributing high-quality documents, images, audio, and video.

Media Controller
A device, usually hand-held, for selecting the program to be displayed or played on a TV
set or a Digital Media Player. Some controllers are purpose-built remote controls designed
for use with a particular devices—a TV set, a Video Recorder or a Digital Media Player,
for example. Some phones and tablets can be programmed via an app to control a particular
media device such as a TV set, a Video Recorder or a Digital Media Player.

Media File
A set of digital data that stores a media item in memory or is used to transmit the item
between devices on a network. See Media.

Media Player
A digital device that plays or displays media files stored on the unit or transmitted to
it from other devices.

Media Renderer
A digital device that can play or display media data sent to it by a network attached
device. A mobile phone, for example can cast an image file stored on the phone to a TV
set. The TV set renders the image data and displays it on the screen where it can be
seen by a larger audience than can conveniently cluster around the phone. The same TV
set might be equipped to render audio and video data sent to it from other devices.

Media Server
A digital network device that stores media files and facilitates access to the files from
client media player devices on the network.

Megabyte
A block of memory that stores 1,048,576 bytes of data.

Memory
Solid-state circuitry for storing digital data. Various types of memory are used for
different purposes. RAM (Random Access Memory) is fast but volatile working memory that
holds data only when powered. Devices load the operating system code and currently
required data into RAM. All other data and code is left stored on slower storage memory.
Files in RAM must be saved to storage memory before a system is powered down, otherwise
changes will be lost.

On some systems, especially PCs, the user must consciously ensure that required files are
saved to storage memory. The File System allows the user to decide where files are saved
provides the facilities for navigating to and managing files.

Other systems automatically save the work in progress on the fly so that the user is never
required to decide whether to save or where to save data that has been created or altered.
Such systems usually start up in the same state they were in when the system was last used.
Phones and tablet operating systems frequently operate in this fashion. Users are often
oblivious of the existence and location of their data files on such devices.

Storage memory uses slower forms of solid-state memory that maintain data when not powered
SSDs, USB Flash drives and Memory Cards, for example. Electro-magnetic, mechanical devices
such as HDDs and USB HDDs and optical mechanical devices such as CD-R and DVD-R drives can
also be used as storage memory.

Microprocessor
An integrated circuit that performs all the functions of a digital computer.

Miracast
A standard for wirelessly transmitting the display of a PC, tablet or phone
to a remote display device such as a TV or data projector.
Miracast emerged on Android devices.
It has since been merged with the Intel WiDi standard to form the WiFi Certified Miracast
standard, which Microsoft has incorporated into its latest operating systems.

Modem
A device for translating digital signals into signals that can be carried by a phone line
and vice versa.

NAS Unit
A Network Accessible Storage device—a unit that attaches to a LAN via Ethernet cable or
WiFi. By definition, a NAS unit acts as a File Server. Some offer a simple shared space
available to all users. Others allow user accounts, user groups and permissions to be set
up to provide individuals and groups of users with secure access to circumscribed sets of
data. Some NAS can be configured to run a Media Server, a Web Server, a Database Server
and a Backup Server. Full-featured NAS units are fitted with multiple storage drives
configured in a RAID array and connect to a Uninterruptible Power Supply (UPS) that
powers the unit down gracefully in the event of a power failure.

NBN
A digital network currently being rolled out across Australia that may eventually connect
every premises to a digital data line that delivers high-speed digital broadband.

Network
A set of digital devices that can exchange data.

Operating System
The program code that enables a digital device to serve the purposes for which it was
designed. When a device is powered on, the operating system loads itself (boots) into
memory, thereby re-installing the software that enables the device to function.
The operating system of a PC, for example, allows the user to control the machine,
and to access and manage data, etc, via a keyboard, a display and a mouse or track pad.
It mounts storage devices. It establishes network connections. It sends data to printers.
It allows the user to install or delete applications and apps. It allows applications
and apps to create files or download files from other devices and save them on local
storage spaces. Some commonly encountered operating systems are:
On Windows PCs, Microsoft Windows 10 and its predecessors;
On Macintosh PC's, OS X 10.11 and its predecessors;
On enterprise computers and servers, versions of Unix from various vendors
On many network devices such a routers, NAS units and Digital Media Players,
versions of Linux;
On Linux PC's, various distributions of Linux;
On iPhone and iPads, iOS 9 and its predecessors;
On Android phones, tablets and media players, various versions of Android.

OS X
The Operating System of Macintosh PCs.

Packet Switching
The process performed by routers and switches to ensure that that data packets sent
across a network arrive at their destinations.

Passphrase
The code a user must supply to join a WiFi device to a LAN.

Password
The code a user must supply, along with a username, to log on to a device or service
on a system.

PC
Personal Computer

Program
Computer code executed by a computer’s CPU to perform a specific function.

Protocol
A set of standards that must be implemented for devices to successfully communicate
over a network. Internet Protocol, for example, defines standards devices must adhere
to if they are to send and received data over the Internet.

PVR
Personal Video Recorder. A set-top box that allows off-air TV broadcasts to be recorded
on an attached USB HDD.

RAM
Random Access Memory. See Memory.

Remote Control
See
Control.

Renderer
A device that translates a stream of digital data into sound or video,

Rendering
The conversion of a stream of digital data into images, or sound or video.

RJ45
The telephone-type plug that terminates CAT5 Cable and plugs into an Ethernet LAN port
on a digital device.

ROM
Read Only Memory. Solid-state ROM circuitry is used in devices to hold essential,
unchangeable data or program code. Optical ROM discs such as Audio CDs, DVD and Blu
Ray discs store audio and video signals in digital, read-only form.

Router
A device on a LAN that handles packet-switching of data being transferred to and from
devices on the LAN and devices on other networks.

Server
1) A digital network device that serves data to networked client devices. 2) Software
running on a server device that provides a particular service to client devices for
example, a File Server, a Media Server or a Database Server.

Share
Part of a computer's file storage area made accessible to others across a network.

Sharing
The setup actions that allow a particular file or folder or entire storage device
to be accessed by other users across a network.

SHF
Super High Frequency, a radio band used by 5 GHz WiFi transceivers.

Solid-State
Silicon-based microchip circuitry

SSD Drive
A device that stores digital data files in solid-state memory circuitry. SSD drives are
faster than HDDs. As costs come down, SSDs are starting to be used in place of HDDs in
PCs and other digital devices.

Storage Capacity
The number of bytes of data a storage device can hold.

Storage Device
A device that stores program code and data.

Stream
A continuous stream of digital data that is transferring a media file to a rendering
device.

Streaming
The act of listening to an audio track or viewing a movie as its data is streamed across
a network by a media server.

Switch
A network device on a LAN that handles packet-switching of data being transferred between
devices on the LAN.

Terabyte
A block of memory that stores 1,099,511,627,776 bytes of data.

UHF
Ultra High Frequency, a radio band used by 2.4 GHz WiFi transceivers.

UPnP
Universal Plug'n Play. A interconnection standard that allows devices from various
manufacturers to interconnect. The DLNA standards follow the UPnP standards that apply
to the interconnection of digital media devices.

USB
Universal Serial Bus, a set of standards for connecting USB peripherals to digital
devices. For example, a USB HDD, a USB Flash Drive and a digital camera will all connect
to a PD and mount as disk volume that can be accessed from the PC's file system. USB is
a diverse that provides for the connection many types of devices including printers,
scanners, cameras, keyboards, mice, track pads, speakers, battery charges, etc.

USB Flash Memory Drive
Solid-state storage memory in a thumb-sized package or smaller that connects to a digital
device via a USB Port.

USB Hard Disk Drive
A hard disk drive in an enclosure that connects to a digital device to provide storage
space. A USB HDD attached to a PC mounts as a volume that can be accessed by the PC’s
File System. A USB HDD attached to a TV or a PVR provides a space on which off-air
broadcasts can be recorded.

USB Port
A connection socket on a digital device that allows a USB peripheral such as Flash drive
to be connected via a USB cable.

User Account
An account on a device that allows access to a subset of the device’s capabilities. (An
admin account provides unrestricted access.) User accounts prevent users from
inadvertently changing system settings. It is good practice to log on to systems with a
user account that has just sufficient access to complete the tasks of the moment, and to
log on as an administrator only when system administration activities are to be undertaken.

Video File
A set of digital data that stores a movie in memory or is used to transmit movie data
between devices on a network.

VPN
Virtual Private Network, a standard for securely accessing data on servers and PCs
across the Internet. A VPN connection allows, for example, a user, when away from home,
to operate or access data stored on a PC or a NAS volume in the home. In effect,
establishing a VPN connection gives a user the same level of access to a remote
device as would be obtained in the the home when attached via Ethernet cable or WiFi.
All transmissions across a VPN connection are encrypted. Transfer rates are limited
to that which the broadband link can sustain. For a VPN connection to be established,
the device in the home and the remote device must have VPN compliant software
installed. The device in the home must be set up to allow a particular user to
establish a VPN connection. When away from home, to set up a connection, the user
would log on to an Internet address that reaches the home device
and supply the required username and password when prompted.

WAN
Wide Area Network. A set of LANs connected via Routers into a larger network to serve
the needs a large business or institution.

WD TV Live HD
A digital media player marketed by Western Digital (No longer in production).

WiDi
A wireless display transmission standard established by Intel. See Miracast.

WiFi
A local area wireless networking technology that allows devices to connect using the 2.4
gigahertz UHF and 5 gigahertz SHF radio bands.

WiFi Access Point
A device that allows devices to connect to a LAN via WiFi. In a small business or home
network, the WiFi Access Point is built into the Modem Router. In an organization such
as a business of a school, multiple WiFi Access Points are put in place ensure that
devices anywhere on the premises obtain a good signal. Some homes install a WiFi Access
Point or WiFi extender to boost the WiFi signal in an area where the WiFi Modem Router
signal is marginal or non-existent.

WiFi Certified Miracast
See Miracast

Windows 10
The most recent operating system released by Microsoft.

WLAN
WiFi LAN. A Local Area Network to which devices can connect via WiFi.